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The HTTPLib library is an HTTP library for NSBasic on PalmOS powered PDAs. It allows an application developer to write NSBasic programs that interact with a web service over the Internet via the HTTP or the, secure, HTTPS protocol.
You could use it to grab a webpage from the Internet. Altough this can be usefull, this library does not understand the HTML stream that will be returned. You would still need to parse the HTML and write up an NSBasic program to visualise it.
Instead, this library is intented to be used to access arbitrary generated data coming from an application server on the Internet. And this opens up a whole new world for the application developer. Instead of an HTML page, you could return a new workschedule for a field engineer or the balance on a bank account.
The application server can be as simple as a CGI script or an ASP page or as complex as an industry strength application server, backed up by a database. Look at the examples section for some ideas.
Actually, this library allows you to leverage the HTTP protocol as a remote method interface (RMI) protocol.
Some ideas for further exploration:
- Field force automation.
- Getting a new work-schedule for a field engineer.
- Remote synchronisation.
- Synchronizing 'on-the-field' data with a remote backend.
- Remote data access.
- Databases that are too big to fit on the device can be accessed remotely, e.g. inventory management.
The figure explains the topology of a typical usage for the HTTPLib library. First the PalmOS PDA connects to the Internet, if already not connected. Typically this is a dial-in connection to an ISP, but it can also be that the PalmOS PDA is connected to a wireless network, using some kind of RF equipment (WLAN, Palm wireless modem, ...). You can even connect the PalmOS PDA by using a wired serial connection to a host computer via PPP or SLIP (Cradle). After the PalmOS PDA has acquired a connection, the request is send out, to a server application, identified by a URL. This application interprets the parameters send to it and takes appropriate action. In it's most simple form, this action can be returning a static HTML page, but it can also trigger a complex database lookup or transaction. After the result has been prepared it is send back to the application on the PDA. This client side application will interpret (parse) the returned datastring and do some client side processing. This can be a simple visualisation or it can be database update or anything else that is required by your application.
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